diff --git a/.lintr b/.lintr
index a9af68366..31ebf6feb 100644
--- a/.lintr
+++ b/.lintr
@@ -2,6 +2,20 @@ linters: all_linters(
     backport_linter("3.6.0", except = c("R_user_dir", "deparse1", "...names")),
     line_length_linter(120L),
     object_overwrite_linter(allow_names = c("line", "lines", "pipe", "symbols")),
+    todo_comment_linter(
+      except_regex = rex::rex(
+        "TODO(",
+        group(or(
+          # GitHub issue number #1234, possibly from another repo org/repo#5678
+          list(maybe(one_or_more(alnum, "-"), "/", one_or_more(alnum, ".", "-", "_")), "#", one_or_more(digit)),
+          # GitHub user
+          one_or_more(alnum, "-"),
+          # version requirement for deprecation notes, e.g. '>3.2.0' --> once 3.2.0 is released, do X
+          list(">", one_or_more(digit, "."))
+        )),
+        ")"
+      )
+    ),
     undesirable_function_linter(modify_defaults(
       defaults = default_undesirable_functions,
       library = NULL,
diff --git a/DESCRIPTION b/DESCRIPTION
index 987e74b42..5cfc49721 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -32,7 +32,7 @@ Imports:
     rex,
     stats,
     utils,
-    xml2 (>= 1.0.0),
+    xml2 (>= 1.3.6),
     xmlparsedata (>= 1.0.5)
 Suggests:
     bookdown,
diff --git a/NAMESPACE b/NAMESPACE
index 00d9ad2e0..6441d5523 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -195,7 +195,7 @@ importFrom(xml2,xml_children)
 importFrom(xml2,xml_find_all)
 importFrom(xml2,xml_find_chr)
 importFrom(xml2,xml_find_first)
+importFrom(xml2,xml_find_int)
 importFrom(xml2,xml_find_lgl)
-importFrom(xml2,xml_find_num)
 importFrom(xml2,xml_name)
 importFrom(xml2,xml_text)
diff --git a/R/brace_linter.R b/R/brace_linter.R
index eebdb90ec..27a35c5a5 100644
--- a/R/brace_linter.R
+++ b/R/brace_linter.R
@@ -74,7 +74,7 @@ brace_linter <- function(allow_single_line = FALSE) {
     )")
   ))
 
-  # TODO (AshesITR): if c_style_braces is TRUE, invert the preceding-sibling condition
+  # TODO(AshesITR): if c_style_braces is TRUE, invert the preceding-sibling condition
   xp_open_curly <- glue("//OP-LEFT-BRACE[
     { xp_cond_open }
     and (
@@ -109,7 +109,7 @@ brace_linter <- function(allow_single_line = FALSE) {
     )"
   ))
 
-  # TODO (AshesITR): if c_style_braces is TRUE, skip the not(ELSE) condition
+  # TODO(AshesITR): if c_style_braces is TRUE, skip the not(ELSE) condition
   xp_closed_curly <- glue("//OP-RIGHT-BRACE[
     { xp_cond_closed }
     and (
@@ -121,7 +121,7 @@ brace_linter <- function(allow_single_line = FALSE) {
   xp_else_closed_curly <- "preceding-sibling::IF/following-sibling::expr[2]/OP-RIGHT-BRACE"
   # need to (?) repeat previous_curly_path since != will return true if there is
   #   no such node. ditto for approach with not(@line1 = ...).
-  # TODO (AshesITR): if c_style_braces is TRUE, this needs to be @line2 + 1
+  # TODO(AshesITR): if c_style_braces is TRUE, this needs to be @line2 + 1
   xp_else_same_line <- glue("//ELSE[{xp_else_closed_curly} and @line1 != {xp_else_closed_curly}/@line2]")
 
   xp_function_brace <- "(//FUNCTION | //OP-LAMBDA)/parent::expr[@line1 != @line2 and not(expr[OP-LEFT-BRACE])]"
diff --git a/R/indentation_linter.R b/R/indentation_linter.R
index 4c968ffff..0e97ec575 100644
--- a/R/indentation_linter.R
+++ b/R/indentation_linter.R
@@ -233,7 +233,7 @@ indentation_linter <- function(indent = 2L, hanging_indent_style = c("tidy", "al
     for (change in indent_changes) {
       change_type <- find_indent_type(change)
       change_begin <- as.integer(xml_attr(change, "line1")) + 1L
-      change_end <- xml_find_num(change, xp_block_ends)
+      change_end <- xml_find_int(change, xp_block_ends)
       if (isTRUE(change_begin <= change_end)) {
         to_indent <- seq(from = change_begin, to = change_end)
         expected_indent_levels[to_indent] <- find_new_indent(
diff --git a/R/lint.R b/R/lint.R
index e7915d856..541006dd7 100644
--- a/R/lint.R
+++ b/R/lint.R
@@ -24,8 +24,6 @@
 #' @param text Optional argument for supplying a string or lines directly, e.g. if the file is already in memory or
 #'   linting is being done ad hoc.
 #'
-#' @aliases lint_file
-# TODO(next release after 3.0.0): remove the alias
 #' @return An object of class `c("lints", "list")`, each element of which is a `"list"` object.
 #'
 #' @examplesIf requireNamespace("withr", quietly = TRUE)
diff --git a/R/lintr-package.R b/R/lintr-package.R
index 898db1445..5531c3f66 100644
--- a/R/lintr-package.R
+++ b/R/lintr-package.R
@@ -15,7 +15,7 @@
 #' @importFrom utils capture.output getParseData getTxtProgressBar globalVariables head relist
 #'   setTxtProgressBar tail txtProgressBar
 #' @importFrom xml2 as_list
-#'   xml_attr xml_children xml_find_all xml_find_chr xml_find_lgl xml_find_num xml_find_first xml_name xml_text
+#'   xml_attr xml_children xml_find_all xml_find_chr xml_find_int xml_find_lgl xml_find_first xml_name xml_text
 #' @rawNamespace
 #' if (getRversion() >= "4.0.0") {
 #'   importFrom(tools, R_user_dir)
diff --git a/R/missing_argument_linter.R b/R/missing_argument_linter.R
index 3565ab5db..419f6535c 100644
--- a/R/missing_argument_linter.R
+++ b/R/missing_argument_linter.R
@@ -58,8 +58,7 @@ missing_argument_linter <- function(except = c("alist", "quote", "switch"), allo
     named_idx <- xml_name(missing_args) == "EQ_SUB"
     arg_id <- character(length(missing_args))
     arg_id[named_idx] <- sQuote(xml_find_chr(missing_args[named_idx], "string(preceding-sibling::SYMBOL_SUB[1])"), "'")
-    # TODO(r-lib/xml2#412-->CRAN): use xml_find_int() instead
-    arg_id[!named_idx] <- xml_find_num(missing_args[!named_idx], "count(preceding-sibling::OP-COMMA)") + 1.0
+    arg_id[!named_idx] <- xml_find_int(missing_args[!named_idx], "count(preceding-sibling::OP-COMMA)") + 1L
 
     xml_nodes_to_lints(
       missing_args,
diff --git a/R/object_usage_linter.R b/R/object_usage_linter.R
index 5d222e232..443c73bc3 100644
--- a/R/object_usage_linter.R
+++ b/R/object_usage_linter.R
@@ -87,8 +87,6 @@ object_usage_linter <- function(interpret_glue = TRUE, skip_with = TRUE) {
         skip_with = skip_with
       )
 
-      # TODO handle assignment functions properly
-      # e.g. `not_existing<-`(a, b)
       res$name <- re_substitutes(res$name, rex("<-"), "")
 
       lintable_symbols <- xml_find_all(fun_assignment, xpath_culprit_symbol)
@@ -211,7 +209,7 @@ parse_check_usage <- function(expression,
   # nocov start
   is_missing <- is.na(res$message)
   if (any(is_missing)) {
-    # TODO (AshesITR): Remove this in the future, if no bugs arise from this safeguard
+    # TODO(AshesITR): Remove this in the future, if no bugs arise from this safeguard
     warning(
       "Possible bug in lintr: Couldn't parse usage message ", sQuote(vals[is_missing][[1L]]), ". ",
       "Ignoring ", sum(is_missing), " usage warnings. Please report an issue at https://github.com/r-lib/lintr/issues.",
diff --git a/R/shared_constants.R b/R/shared_constants.R
index 8e6255f20..d581c7e35 100644
--- a/R/shared_constants.R
+++ b/R/shared_constants.R
@@ -243,18 +243,7 @@ extract_glued_symbols <- function(expr, interpret_glue) {
   if (!isTRUE(interpret_glue)) {
     return(character())
   }
-  # TODO support more glue functions
-  # Package glue:
-  #  - glue_sql
-  #  - glue_safe
-  #  - glue_col
-  #  - glue_data
-  #  - glue_data_sql
-  #  - glue_data_safe
-  #  - glue_data_col
-  #
-  # Package stringr:
-  #  - str_interp
+  # TODO(#2448): support more glue functions
   # NB: position() > 1 because position=1 is <expr><SYMBOL_FUNCTION_CALL>
   glue_call_xpath <- "
     descendant::SYMBOL_FUNCTION_CALL[text() = 'glue']
diff --git a/R/todo_comment_linter.R b/R/todo_comment_linter.R
index e2161fd78..cbdbb5619 100644
--- a/R/todo_comment_linter.R
+++ b/R/todo_comment_linter.R
@@ -9,22 +9,17 @@
 #' @examples
 #' # will produce lints
 #' lint(
-#'   text = "x + y # TODO",
-#'   linters = todo_comment_linter()
-#' )
-#'
-#' lint(
-#'   text = "pi <- 1.0 # FIXME",
-#'   linters = todo_comment_linter()
+#'   text = "x + y # TOODOO",
+#'   linters = todo_comment_linter(todo = "toodoo")
 #' )
 #'
 #' lint(
-#'   text = "x <- TRUE # hack",
-#'   linters = todo_comment_linter(todo = c("todo", "fixme", "hack"))
+#'   text = "pi <- 1.0 # FIIXMEE",
+#'   linters = todo_comment_linter(todo = "fiixmee")
 #' )
 #'
 #' lint(
-#'   text = "x <- TRUE # TODO(#1234): Fix this hack.",
+#'   text = "x <- TRUE # TOODOO(#1234): Fix this hack.",
 #'   linters = todo_comment_linter()
 #' )
 #'
diff --git a/R/unnecessary_concatenation_linter.R b/R/unnecessary_concatenation_linter.R
index ed263bfb1..14d000b2d 100644
--- a/R/unnecessary_concatenation_linter.R
+++ b/R/unnecessary_concatenation_linter.R
@@ -100,7 +100,7 @@ unnecessary_concatenation_linter <- function(allow_single_expression = TRUE) { #
     c_calls <- xml_find_all(xml_calls, call_xpath)
 
     # bump count(args) by 1 if inside a pipeline
-    num_args <- as.integer(xml_find_num(c_calls, num_args_xpath)) +
+    num_args <- xml_find_int(c_calls, num_args_xpath) +
       as.integer(!is.na(xml_find_first(c_calls, to_pipe_xpath)))
     # NB: the xpath guarantees num_args is 0, 1, or 2. 2 comes
     #   in "a" %>% c("b").
diff --git a/R/xml_nodes_to_lints.R b/R/xml_nodes_to_lints.R
index 323a0f5be..a7a081117 100644
--- a/R/xml_nodes_to_lints.R
+++ b/R/xml_nodes_to_lints.R
@@ -5,7 +5,7 @@
 #'
 #' @details
 #' The location XPaths, `column_number_xpath`, `range_start_xpath` and `range_end_xpath` are evaluated using
-#' [xml2::xml_find_num()] and will usually be of the form `"number(./relative/xpath)"`.
+#' [xml2::xml_find_int()] and will usually be of the form `"number(./relative/xpath)"`.
 #' Note that the location line number cannot be changed and lints spanning multiple lines will ignore `range_end_xpath`.
 #' `column_number_xpath` and `range_start_xpath` are assumed to always refer to locations on the starting line of the
 #' `xml` node.
diff --git a/R/xp_utils.R b/R/xp_utils.R
index 621bc13b4..a46cea5ab 100644
--- a/R/xp_utils.R
+++ b/R/xp_utils.R
@@ -107,7 +107,7 @@ xp_find_location <- function(xml, xpath) {
   } else if (identical(xpath, "number(./@col2)")) {
     as.integer(xml_attr(xml, "col2"))
   } else {
-    as.integer(xml_find_num(xml, xpath))
+    xml_find_int(xml, xpath)
   }
 }
 
@@ -118,7 +118,7 @@ xp_find_location <- function(xml, xpath) {
 #'   way to XPath 2.0-ish support by writing this simple function to remove comments.
 #'
 #' @noRd
-xpath_comment_re <- rex::rex(
+xpath_comment_re <- rex(
   "(:",
   zero_or_more(not(":)")),
   ":)"
diff --git a/man/lint.Rd b/man/lint.Rd
index 54d1bbe48..efc4d2925 100644
--- a/man/lint.Rd
+++ b/man/lint.Rd
@@ -2,7 +2,6 @@
 % Please edit documentation in R/lint.R
 \name{lint}
 \alias{lint}
-\alias{lint_file}
 \alias{lint_dir}
 \alias{lint_package}
 \title{Lint a file, directory, or package}
diff --git a/man/xml_nodes_to_lints.Rd b/man/xml_nodes_to_lints.Rd
index 6a53b05a1..78afb95a9 100644
--- a/man/xml_nodes_to_lints.Rd
+++ b/man/xml_nodes_to_lints.Rd
@@ -48,7 +48,7 @@ linter logic into a \code{\link[=Lint]{Lint()}} object to return.
 }
 \details{
 The location XPaths, \code{column_number_xpath}, \code{range_start_xpath} and \code{range_end_xpath} are evaluated using
-\code{\link[xml2:xml_find_all]{xml2::xml_find_num()}} and will usually be of the form \code{"number(./relative/xpath)"}.
+\code{\link[xml2:xml_find_all]{xml2::xml_find_int()}} and will usually be of the form \code{"number(./relative/xpath)"}.
 Note that the location line number cannot be changed and lints spanning multiple lines will ignore \code{range_end_xpath}.
 \code{column_number_xpath} and \code{range_start_xpath} are assumed to always refer to locations on the starting line of the
 \code{xml} node.
diff --git a/tests/testthat/test-get_source_expressions.R b/tests/testthat/test-get_source_expressions.R
index 917a414ed..d58f547ba 100644
--- a/tests/testthat/test-get_source_expressions.R
+++ b/tests/testthat/test-get_source_expressions.R
@@ -240,8 +240,8 @@ test_that("returned data structure is complete", {
   expect_identical(full_expr$content, lines_with_attr)
   expect_identical(nrow(full_expr$full_parsed_content), 2L * length(lines))
   expect_identical(
-    xml2::xml_find_num(full_expr$full_xml_parsed_content, "count(//SYMBOL)"),
-    as.numeric(length(lines))
+    xml2::xml_find_int(full_expr$full_xml_parsed_content, "count(//SYMBOL)"),
+    length(lines)
   )
   expect_true(full_expr$terminal_newline)
 
diff --git a/tests/testthat/test-todo_comment_linter.R b/tests/testthat/test-todo_comment_linter.R
index 922819344..103f9c8fc 100644
--- a/tests/testthat/test-todo_comment_linter.R
+++ b/tests/testthat/test-todo_comment_linter.R
@@ -1,5 +1,5 @@
 test_that("returns the correct linting", {
-  linter <- todo_comment_linter(todo = c("todo", "fixme"))
+  linter <- todo_comment_linter()
   lint_msg <- rex::rex("Remove TODO comments.")
 
   expect_lint('a <- "you#need#to#fixme"', NULL, linter)